In a conventional developing process for photoresist (hereinafter, simply referred to as “resist”), a developing solution is supplied through a nozzle onto a surface of a semiconductor wafer (hereinafter, simply referred to as a “wafer”) that has been coated with resist and exposed to light via a preset pattern. To obtain process uniformity in a wafer surface, the developing solution is supplied such that a liquid film is uniformly formed on the entire surface of the wafer, and the resist is dissolved by the liquid film.
To form the liquid film of the developing solution, there is known a method (puddle type developing process) for accumulating liquid on the entire surface of the wafer by discharging the developing solution onto the stationary wafer while moving a nozzle having an elongated discharge port, or there is known a method (puddless type developing process) for supplying the developing solution in, e.g., a diametric direction of the wafer while rotating the wafer around a vertical axis and coating the developing solution on the wafer by a centrifugal force.
In consideration of the composition of materials of the resist, a reaction between the developing solution and the resist may progress for a relatively short time. In the aforementioned methods, however, a great amount of developing solution has been used to form a uniform liquid film, and a great amount of time has been taken to supply the developing solution onto the wafer. Since the process of supplying the developing solution is so time-consuming, a certain amount of time, e.g., about 30 seconds to about 60 seconds has been required till the reaction between the developing solution and the resist is completed after the supply of the developing solution is begun.
Meanwhile, a liquid immersion exposure process may be performed as an exposure process for a wafer. To suppress an influence of a liquid used in this liquid immersion exposure process upon the wafer, a high water-repellent resist tends to be used. If the high water-repellent resist is used, however, some portions on the resist may not be wet with the developing solution when the resist is developed by the aforementioned methods. Accordingly, to form a uniform liquid film of the developing solution for the high water-repellent resist, a greater amount of developing solution may be required, which may cause increase of processing cost and supply time for the developing solution. As a result, high throughput of a coating and developing apparatus may not be achieved.
In Patent Document 1, it is disclosed that mist of a developing solution is supplied into a chamber accommodating a substrate therein. The substrate is supported by a hot plate with a certain gap maintained therebetween, and a temperature of the substrate is adjusted by the hot plate. In this method, the temperature of the substrate is set to be lower than a temperature of the mist of the developing solution such that a liquid film of the developing solution is formed by condensing the developing solution on a surface of the substrate. However, Patent Document 1 does not mention anything about a method for condensing vapor of the developing solution on a substrate mounted on a temperature control plate.
Patent Document 1: Japanese Patent Laid-open Publication No. 2005-277268 (paragraphs [0139] and [0141])